The modern pace of life dictates its own demands, and stable communication becomes critical in the most unexpected places. Often, in apartments with thick walls, basements, or remote areas of the city, cellular signal strength drops to critical levels, making urgent calls impossible. In such situations, VoWiFi technology comes to the rescue, allowing voice traffic to be transmitted over an internet connection.
MTS is actively implementing and supporting this feature, allowing subscribers to stay connected even in areas with only one signal or no coverage at all. Using Wi-Fi for calls not only solves the problem of "dead zones" but also often provides higher sound quality thanks to the wide data channel. However, for this feature to work correctly, you need to configure a number of settings on your smartphone and ensure that your tariff plan supports the service.
In this article, we'll cover in detail how to activate Wi-Fi calling on MTS devices, which phone models support this feature, and what to do if the desired icon doesn't appear in the status bar. You'll learn about pricing details and understand how this feature differs from popular messaging apps. The main advantage of the technology The advantage is that incoming and outgoing calls are made from your regular number, and the person you are talking to does not need to install any additional applications.
What is VoWiFi and how does it work on MTS?
The technology in question is called Voice over Wi-Fi, or VoWiFi for short. It works by digitizing the voice signal and transmitting it over IP protocols, just like any other internet data. For MTS, this means the signal bypasses cellular base stations and travels directly through the nearest global network access point.
It is important to understand that this is not just an analogue of Skype or WhatsApp. VoWiFi It's deeply integrated into the phone's system, working within the Phone app. When you dial a number, the smartphone automatically analyzes network availability. If the cellular signal is weak and Wi-Fi is stable, the device will switch to voice transmission over the internet without interrupting the connection.
The key is transparency for the user. You don't need to open separate apps or ask the other person to do the same. You dial a number from your standard phone book, and the call goes through. Connection quality In this case, it directly depends on the speed and stability of your wireless router, and not on the load on the nearest cell phone tower.
MTS supports this technology on most modern tariff plans, including archived ones, provided the subscriber's device is technically compatible. This significantly expands coverage, especially in office buildings with shielded surfaces or in country houses.
Checking device and tariff compatibility
Before setting up, make sure your smartphone and SIM card are ready for VoWiFi. Not all phone models, even those released in recent years, have firmware support for this feature for Russian carriers. The region in which the device was released also matters.
The SIM card must also be up-to-date. If you're using a SIM card that's been around for many years and has never been replaced, you may need to upgrade it at a mobile phone store. However, in most cases, MTS allows you to activate the service remotely if your subscriber profile is already up-to-date.
You can check your plan through your personal account or by contacting customer support. MTS doesn't charge a separate fee for activating the feature, but the traffic consumed during calls is charged according to your minute package. If you have unlimited minutes, your calls will remain unlimited over Wi-Fi.
For an accurate diagnosis, you can use the following algorithm:
- 📱 Make sure your smartphone model is officially sold in the Russian Federation or has a global firmware.
- 📡 Check that the SIM card is installed in a slot that supports 4G/LTE (usually this is slot 1).
- 💳 Make sure that the number does not have any blocking services or restrictions.
- 🔄 Update your smartphone's operating system to the latest available version.
It's worth noting that some custom Android firmware may not contain the necessary certificates for VoWiFi support with Russian operators. In this case, you may need to reflash the firmware or use the engineering menu, which is not recommended without experience.
Instructions for enabling VoWiFi on Android
The process for activating this feature on Android smartphones may vary slightly depending on the manufacturer and operating system version. However, the general steps are the same for most devices, including Samsung, Xiaomi, and other popular brands.
First, go to your device's main settings. Find the section for connections or wireless networks. Depending on your phone model, this may be called "Connections," "SIM cards and mobile networks," or simply "Mobile network."
Inside the menu, find the switch labeled "Wi-Fi Calling" or "Wi-Fi Calling." Activate this sliderIf the system asks for confirmation or prompts you to select a network priority, select "Prefer Wi-Fi" or "Always use Wi-Fi" if you are in an area with poor cellular coverage.
Once enabled, a Wi-Fi indicator should appear in the top status bar next to the Wi-Fi icon. This indicator may look different on different phones: a phone handset with a Wi-Fi symbol, the words "Wi-Fi Call," or simply a phone icon with the letter "W."
⚠️ Attention: On some smartphone models (for example, certain Xiaomi or Huawei versions), the menu item may be hidden. In this case, try entering the code in the dialing field.
##86938#or##86938##to open the hidden engineering menu of VoWiFi settings, if it is available on your firmware.
If the feature still doesn't work after all these steps, try rebooting your device. The system often takes time to register with the operator's IMS network after the feature is first enabled.
Setting up Wi-Fi calling on iPhone (iOS)
Apple smartphone owners are fortunate to have a more unified interface. Setting up VoWiFi on an iPhone is virtually identical on all models, starting with the iPhone 6s, as long as you have the latest version of iOS installed. The iOS settings interface is very user-friendly and intuitive.
Open the Settings app and go to the Cellular section. If you have a dual-SIM phone, select the MTS SIM card for which you want to enable the feature. Next, find the "Wi-Fi Calling" option and toggle the switch to on.
The system will alert you that your operator will receive your location information for emergency services. This is a standard procedure for registering your address for emergency calls (112), which is required for the technology to work. Click "Enable" to confirm.
After successful activation, the message "MTS Wi-Fi" will appear in the upper left corner of the screen (or in the notch on newer models). This indicates that the phone is ready to make and receive calls over the wireless network. If the icon disappears, the connection to the router has been lost or the cellular signal has become strong enough for a normal call.
Also, make sure your privacy settings allow location access for system services, at least temporarily, for the initial registration.
Pricing and features of use
One of the most common questions MTS subscribers have concerns the cost of such calls. Many fear that their data will be deducted from their basic gigabyte package or, worse, billed separately. However, the operator's rules on this matter are quite transparent.
Wi-Fi calls are charged the same as regular cellular voice calls. If you have a minute bundle included in your plan, these will be deducted from it. If you have unlimited minutes, Wi-Fi calls will also be free within your plan. MTS does not charge any additional fees for using the technology.
Regarding internet traffic, there's an important nuance. Traffic used directly for voice transmission in VoWiFi mode It is not charged and does not take up any gigabytes from your package.The carrier accounts for this traffic separately. However, if you scroll through your social media feed or watch videos during a call, this traffic will be used as normal.
A comparison of pricing conditions is presented in the table below:
| Parameter | Regular call (GSM/3G/4G) | Calling via Wi-Fi (VoWiFi) | Call via messenger |
|---|---|---|---|
| Package minutes consumption | Yes | Yes | No |
| Internet traffic consumption | No | No (for voice) | Yes (from the package) |
| Need for an application | No | No | Yes (both interlocutors) |
| Sound quality | Depends on the tower | High (HD Voice) | Depends on the speed |
Therefore, using VoWiFi is a cost-effective way to stay connected, especially if you're running low on minutes but have unlimited home internet. This is also true for roaming, where incoming calls over Wi-Fi may be free, unlike standard incoming calls in international roaming, but it's best to check roaming terms and conditions separately.
Troubleshooting connection issues and errors
Despite the ease of setup, users may encounter a number of technical difficulties. The most common issue is the absence of the VoWiFi icon after enabling the feature in settings. This may indicate that the phone is unable to register with the carrier's IMS network.
Often, the problem lies in the router's security settings. Some home internet providers or corporate networks block ports required for voice traffic. The issue may also lie in the IPv6 protocol, which is not yet properly supported by all operators for voice services.
⚠️ Attention: If you use public Wi-Fi networks in cafes or airports with browser-based authentication (captive portal), calls won't work. Voice calls require a persistent connection, and the captive portal interrupts this process.
Another possible cause could be "Data Saver" or "Airplane Mode" being enabled with only Wi-Fi enabled. Make sure your cellular network is active, even if there's no signal. Your phone must periodically contact your carrier's network to maintain a connection.
If nothing helps, try the following:
- 🔁 Completely reboot your smartphone and router.
- 📲 Remove the SIM card and reinsert it, making sure the contacts are clean.
- ⚙️ Reset your network settings to factory settings (not to be confused with a full reset of your phone).
- 📞 Call MTS technical support to check the service status on the network side.
Sometimes, temporarily disabling 4G/LTE and switching the phone to 3G/2G mode, then back, helps. This forces the device to re-register with the network and update its service profile.
How is VoWiFi different from instant messaging calls?
Many users confuse Wi-Fi calling from their carrier with voice calls on WhatsApp, Telegram, or Viber. Although both methods technically use an internet connection, their operating principles and capabilities are fundamentally different.
The main difference is identification. When calling via VoWiFi, you're calling a regular phone number. Your caller may not have a smartphone, internet access, or even a push-button phone. To them, it will appear as a regular incoming call. With messaging apps, both parties must have the same account and app installed.
Additionally, VoWiFi supports emergency calls with geolocation (where implemented by the operator), which is critical for security. Messaging apps don't offer this guarantee, as they don't have a direct connection to emergency services infrastructure.
Stability is also worth mentioning. VoWiFi technology prioritizes the voice packet, ensuring lower latency and dropouts compared to OTT services (messengers), which share the channel with all other apps running in the background.
Will Wi-Fi calling work if the SIM card is blocked?
No, if your SIM card is blocked by the operator (for example, due to non-payment) or lost, VoWiFi will not work. To register on the IMS network, you need an active SIM card with a positive or zero balance to authenticate. However, if you have an active SIM card in slot 2 and a blocked one in slot 1, you will be able to make Wi-Fi calls from the second SIM card (if it's active).
Is it possible to make calls via Wi-Fi while roaming internationally?
Yes, technically it's possible. If you're abroad and connected to local Wi-Fi, you can call Russian numbers. These calls are usually charged according to your "Like Home" plan or MTS roaming packages, which are often cheaper than standard incoming and outgoing calls when roaming on local networks. However, be sure to check the roaming terms before your trip.
Why does the Wi-Fi Call icon disappear during a call?
This can happen if the Wi-Fi signal quality has deteriorated sharply, and the phone has automatically switched to the cellular network (handover). If the icon has disappeared completely, the router may have rebooted or the router may have run out of data (in rare cases, blocked by the carrier).